for diffraction limited resolution. Lf we take into 
consideration various degradation factors, for example the 
effect of atmosphere, imcompleteness of hardware system, we 
must extend the aperture a little more. Therefore, we assumed 
l m aperture as an actually required diameter of telescope. 
Another assumptions are the glass material BK-7 for correcting 
plate and 1.5 for parameter k which determines the radius of 
neutral zone. Then, utilizing equation (3), we can fix the 
parameters «€ , A and R as follows: 
(3.68616 x 1079 
(à » 3.92868 x 10713 
R = 1.06825 x 10% mm 
From these parameters, non-spherical coefficients of correcting 
plate are determined, and ray trace, aberrations, spot diagram 
and OTF are calculated. 
3. Calculation of optical performances 
Calculations of aberrations and OTF are performed by wave 
optics, so the calculated results will give physical insight of 
the system performances. Incidentally geometrical optics 
sometimes gives too superior results for such a reflecting 
system. The focal plane of Schmidt telescope is spherical as 
shown. in PFPig..2,. F. The spot-diagrams of on axis and semi- 
field angle 1.65 degree on this curved focal plane are shown in 
Fig. 74a), {b)iand-the spot diagram at 1.65 degree on flat 
plane F' is shown in Fig. 7, (c) for comparison. The former 
two spot diagrams are smaller than the assumed photodiode 
aperture 14 um, but the latter spot diagram on flat plane is 
large extraordinarily. Fig. 8 is the OTF for Fig. 7 (b). 'It 
is clear that ‘the OTF value at the cut off ‘frequency of 
photodiode aperture 14 um is about 0.67 for both tangential and 
sagital directions. This means that the conical scan utilizes 
the curved focal plane itself gives sufficient performance for 
100 m spatial resolution from geosynchronous orbit. 
4. Conclusion 
100 m spatial resolution at l.l um wave length can be realized 
with good performance utilizing conical scan on the curved 
focal plane of Schmidt telescope. The diameter of the 
telescope is 1 m and the focal length is about 5 m. This 
dimension is rather small compared to the space telescope and 
it's realization is not so difficult. The observation from 
geosynchronous orbit is a'staring type and sufficient 
integration time for signal will be obtained. By focal plane 
construction we can extend the image to surrounding sea area of 
the Japan islands and to other area, for example, the Chinese 
continent area. 
Reference 
1. Handbook of Optics, Optical Society Of America, 1978, 
McGraw-Hill. 
79